Currently, the third generation mobile communication system standardization organization, i.e. the 3rd Generation Partnership Project (3GPP), has initiated a Long Term Evolution (LTE) research project of 3G radio interface technologies. Along with development of the research, an LTE system has been designed to support two types of frame structures, i.e. frame structure types 1 and 2, the frame structure type 2 is preferably used in a radio frame for service transmission in an LTE TDD system.
A radio frame with the frame structure type 2 includes 2 half-frames, each of which consists of 7 normal time slots and one special time slot zone. The special time slot zone includes 3 special time slots, i.e., a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP) for a switching point from a downlink time slot to an uplink time slot, and an Uplink Pilot Time Slot (UpPTS). The length of the GP limits directly a cell coverage radius. Currently, the DwPTS, GP, and UpPTS in a radio frame of the frame structure type 2 are fixed in length, thus a varying cell coverage area cannot be supported when the radio frame is used for service transmission.